1. Field of the Invention
The present invention relates to a vacuum cleaner.
2. Description of the Related Art
Vacuum cleaners typically include a vacuum motor and an air pervious bag for collecting material such as dust and other small particulate material. The vacuum motor induces an air flow through the bag and entrained material is collected in the bag. With known vacuum cleaners it is found that when the vacuum cleaner is new the degree of air flow generated through the bag by means of the vacuum motor is good and collection of material is achieved efficiently.
The efficiency of collection of material may be sustained if the vacuum cleaner is maintained regularly. However, it is often the case that vacuum cleaners are not maintained properly and this can then cause a build up of accumulated material in the bag. In this case the air flow is gradually reduced and thus the efficiency of collection of material is correspondingly reduced.
Furthermore, the reduced air flow leads to reduction of the cooling effect of the air on the vacuum motor.
In a backpack type vacuum cleaner, the orientation, in use, of the vacuum cleaner is such that a vacuum motor locates below a collection chamber, the collection chamber being provided with an air pervious collection bag. In operation, the motor creates a suction force which acts to draw air from an inlet located above the bag through the bag and the motor to an outlet located below the motor. With this configuration, as the bag fills with dust or particulate material, holes in the bag become blocked and the resistance to air flow caused by the bag is increased. As a result, over time, the more the vacuum cleaner is used, the lower the suction force of the vacuum cleaner and the lower the cooling effect of the air flow on the motor.
The present invention provides an apparatus which seeks, among other things, to alleviate the above mentioned problems.
In accordance with one aspect of the present invention there is provided a vacuum cleaner apparatus which includes a vacuum motor, an air pervious membrane and an air pervious material collection bag, the vacuum motor being arranged to draw air downwardly in turn through the bag, the said membrane, and the motor so that, in use, the bag retains material entrained in the air, wherein there is also provided a spacing means located intermediate the said membrane and the bag for orienting the bag such that a first portion of the bag is adjacent the said membrane and a second portion of the bag is spaced from the said membrane.